<style>
    * {
        margin: 0;
        padding: 0;
    }
    li {
        list-style: none;
    }
    .header {
        height: 70px;
        background: cyan;
    }
    .banner {
        width: 1000px;
        height: 200px;
        margin: 10px auto;
        background: cyan;
    }
    .box {
        width: 1000px;
        height: 300px;
        margin: 0 auto;
        background: cyan;
    }
    .box ul li {
        float: left;
        width: 192px;
        height: 300px;
        margin-right: 10px;
        background: skyblue;
    }
    .box ul li:last-child {
        margin-right: 0;
    }
    .footer {
        height: 120px;
        margin-top: 10px;
        background: cyan;
    }
</style>

<div class="header">header</div>
<div class="banner">banner</div>
<div class="box">
    <ul>
        <li>盒子1</li>
        <li>盒子2</li>
        <li>盒子3</li>
        <li>盒子4</li>
        <li>盒子5</li>
    </ul>
</div>
<div class="footer">footer</div>